This invention relates, in general, to the field of messaging, and in particular, to linking topics in a publish/subscribe messaging environment.
In a messaging environment where the publish/subscribe paradigm is being used, typically a hierarchy of topics is created where topics further into the hierarchy are more specific to a particular area of interest. For example /SPORT/FOOTBALL/CHELSEA would describe a hierarchy for the Chelsea (within London) football team results. It is possible to subscribe to multiple topics using a wildcard, for example subscribing on /SPORT/FOOTBALL/# would lead to football results for all teams being delivered to the subscriber.
There may be other distinct parts of the topic tree which have a common sub-theme, for example, /NEWS/LONDON. While the themes of both parts of these trees may overlap, there is no commonality in the topic string, or in other words, the themes are on different branches of a tree. It would, therefore, require at least two subscriptions to be able to subscribe to both London-based topics. If a further topic string related to London but with no commonality in the topic string was introduced, it would require a further subscription to get that information.